1. Field of the Invention
This invention relates to tamper indicating closures. More particularly, the invention relates to tamper indicating closures of the type in which a tamper indicating band is spaced from the bottom of the cylindrical skirt of a standard threaded cap by a number of circumferentially spaced frangible webs. The band has an inwardly directed bead which engages a flange on the container neck below the threads when the cap is initially threaded onto the container. When the cap is unthreaded, the bead on the tamper indicating band engages the flange on the container neck preventing axial movement of the band past the container flange as the cap is being threaded off so that the webs are stretched and fractured leaving the band on the container neck as the cap is removed. As an alternative to an inwardly directed bead on the tamper indicating band, spaced ratchet teeth can be used which engage spaced ratchet teeth on the container neck. Stop surfaces on the ratchet teeth engage, preventing further rotation and axial movement so that the webs are stretched and fractured.
2. Description of the Related Art
Conventional sealing means have been used with this type of tamper indicating closure such as a gasket located in the cap which compresses between the top of the cap and the container lip. Other types of seals have been used such as a flange or fin which is molded integrally with the cap top engaging the container lip or a plug which depends from the cap engaging inside of the container neck have also been used. Normally these conventional seals are satisfactory since the seal integrity is maintained until initial opening and they can be resealed after the tamper indicating band has been fractured from the cap by merely applying the initial sealing force. However, it has been discovered that when this type of closure is applied to a plastic container having a liquid product, that the cap can be backed off or unthreaded sufficiently to break the seal before the frangible webs are broken particularly if pressure is applied to the plastic bottle to force the liquid past the seal. This has caused a problem with the packaging of such products as liquor products in which the closure can be partially unthreaded to allow the removal of a portion of the product by squeezing the container walls and replacing the removed products with water by immersing the closure in water and releasing the depressed or deformed container. When the closure is returned to its tightened condition, there is no evidence of tampering.
It is to the solution of this tampering problem that the present invention is directed.